William Bonney, known as 'Billy the Kid' befriends a man known as 'The Englishman'. His friend is murdered by corrupt businessmen. Bonney's plan for revenge, hunting down and killing all responsible, endangers not only his surviving loved ones, but the international peace set up for the entire territory.

The title refers to the belief that Billy the Kid was left handed, and he shoots left handed in the film, though it is now known that this was a false conclusion drawn from a reversed photograph.